4 files changed, 75 insertions, 6 deletions

diff --git a/archive.h b/archive.h
index b43fe87..bcadb70 100644
--- a/archive.h
+++ b/archive.h
@@ -101,4 +101,7 @@ int mboxBody(FILE *file, char *body);
 
 int htmlEnvelope(FILE *file, const struct Envelope *envelope);
 
-int atomEnvelope(FILE *file, const struct Envelope *envelope);
+int atomEntryHead(FILE *file, const struct Envelope *envelope);
+int atomEntryTail(FILE *file);
+int atomFeedHead(FILE *file, const struct Envelope *envelope);
+int atomFeedTail(FILE *file);
diff --git a/atom.c b/atom.c
index 6692acc..2851e3c 100644
--- a/atom.c
+++ b/atom.c
@@ -22,13 +22,16 @@
 
 #include "archive.h"
 
-int atomEnvelope(FILE *file, const struct Envelope *envelope) {
-	struct Variable idVars[] = {
-		{ "messageID", envelope->messageID },
+static char *atomID(const char *messageID) {
+	struct Variable vars[] = {
+		{ "messageID", messageID },
 		{0},
 	};
-	char *id = templateURL("mailto:?In-Reply-To=[messageID]", idVars);
+	return templateURL("mailto:?In-Reply-To=[messageID]", vars);
+}
 
+int atomEntryHead(FILE *file, const struct Envelope *envelope) {
+	char *id = atomID(envelope->messageID);
 	char date[sizeof("0000-00-00T00:00:00Z")];
 	strftime(date, sizeof(date), "%FT%TZ", gmtime(&envelope->utc));
 	struct Variable vars[] = {
@@ -54,3 +57,43 @@ int atomEnvelope(FILE *file, const struct Envelope *envelope) {
 	free(id);
 	return error;
 }
+
+int atomEntryTail(FILE *file) {
+	int n = fprintf(file, "</entry>\n");
+	return (n < 0 ? n : 0);
+}
+
+int atomFeedHead(FILE *file, const struct Envelope *envelope) {
+	char *id = atomID(envelope->messageID);
+	char date[sizeof("0000-00-00T00:00:00Z")];
+	strftime(date, sizeof(date), "%FT%TZ", gmtime(&(time_t) { time(NULL) }));
+	struct Variable vars[] = {
+		{ "subject", envelope->subject },
+		{ "from.name", addressName(envelope->from) },
+		{ "from.mailbox", envelope->from.mailbox },
+		{ "from.host", envelope->from.host },
+		{ "date", date },
+		{ "id", id },
+		{ "q", "?" },
+		{0},
+	};
+	const char *Feed = TEMPLATE(
+		<[q]xml version="1.0" encoding="utf-8"[q]>
+		<feed xmlns="http://www.w3.org/2005/Atom">
+		<title>[subject]</title>
+		<author>
+			<name>[from.name]</name>
+			<email>[from.mailbox]@[from.host]</email>
+		</author>
+		<updated>[date]</updated>
+		<id>[id]</id>
+	);
+	int error = templateRender(file, Feed, vars, escapeXML);
+	free(id);
+	return error;
+}
+
+int atomFeedTail(FILE *file) {
+	int n = fprintf(file, "</feed>\n");
+	return (n < 0 ? n : 0);
+}
diff --git a/concat.c b/concat.c
index 2c58d8a..eeab073 100644
--- a/concat.c
+++ b/concat.c
@@ -119,14 +119,36 @@ void concatData(struct List threads, struct List items) {
 	if (error || file.st_mtime < uidNewest(flat, "mbox")) {
 		FILE *mbox = fopen(path, "w");
 		if (!mbox) err(EX_CANTCREAT, "%s", path);
+
 		for (size_t i = 0; i < flat.len; ++i) {
 			uint32_t uid = dataCheck(flat.ptr[i], Number).number;
 			error = concatFile(mbox, uidPath(uid, "mbox"));
 			if (error) err(EX_IOERR, "%s", path);
 		}
+
 		error = fclose(mbox);
 		if (error) err(EX_IOERR, "%s", path);
 	}
 
+	path = threadPath(envelope.messageID, "atom");
+	error = stat(path, &file);
+	if (error || file.st_mtime < uidNewest(flat, "atom")) {
+		FILE *atom = fopen(path, "w");
+		if (!atom) err(EX_CANTCREAT, "%s", path);
+
+		error = atomFeedHead(atom, &envelope);
+		if (error) err(EX_IOERR, "%s", path);
+
+		for (size_t i = 0; i < flat.len; ++i) {
+			uint32_t uid = dataCheck(flat.ptr[i], Number).number;
+			error = concatFile(atom, uidPath(uid, "atom"));
+			if (error) err(EX_IOERR, "%s", path);
+		}
+
+		error = atomFeedTail(atom)
+			|| fclose(atom);
+		if (error) err(EX_IOERR, "%s", path);
+	}
+
 	listFree(flat);
 }
diff --git a/export.c b/export.c
index 3e0933d..dcd6b18 100644
--- a/export.c
+++ b/export.c
@@ -134,7 +134,8 @@ void exportData(struct List items) {
 	path = uidPath(uid, "atom");
 	file = fopen(path, "w");
 	if (!file) err(EX_CANTCREAT, "%s", path);
-	error = atomEnvelope(file, &envelope)
+	error = atomEntryHead(file, &envelope)
+		|| atomEntryTail(file)
 		|| fclose(file);
 	if (error) err(EX_IOERR, "%s", path);